Why is the machine waking up?

Use the command line to find what causes the PC to wake up

 

Sometimes a machine will apparently decide to wake up for no reason, other than the fact it's had enough of being in sleep mode. Although not a big problem, this can be frustrating for users. The first port of call when looking into a wake up issue is to crack open the cmd line. Using elevated privilidges, open up the cmd prompt and enter:

powercfg –lastwake
This will return a result which will show which device, if any, was responsible for causing the last wake up.

If you need to view the list of those devices capable of waking up a machine, enter the following:

powercfg -devicequery wake_armed
This will return a list of all those devices which currently have the power to wake up your machine.

The powercfg line can be useful for troubleshooting other power related issues:

powercfg /list
This will show all the power policies which are currently being applied to your machine.

For a complete list of commands which can be used see the MS list here - http://technet.microsoft.com/en-us/library/hh824902.aspx
 

Prevent a particular device from waking your PC

There are two easy ways to do this, either via the command line or through Device Manager.

 

CMD Line

 

powercfg /devicedisabledwake "Microsoft USB IntelliMouse Optical"This will prevent the device in quotation marks from waking up the machine.

 

Device Manager

 



Assuming it's not one of the peripheral devices which is somehow waking it up from sleep/power off mode, then the most likely suspect will be the Network card.

1. Open Device Manager. A quick way to do this is to type “device” (without quotes) in the Start menu search bar and then click on “Device Manager”
2. Expand the "Mice and other Pointing Devices" list
3. Right-click the Microsoft USB InelliMouse optical and choose “Properties”.
4. In the dialog that opens, click the tab “Power Management”
5. Remove the tick next to “Allow this device to wake the computer”
6. Click “OK” and exit Device Manager